No you really want them on the bottom. Also you really want to use the foot ones as they can burn on alot less O2. I have been using these disposable warmers since they came out in the 80's so trust me. Now the do build one that is the whole length of your foot. I also sit all day sits in sub-zero weather here in MN, and I will still prefer to use REALLY GOOD boots over warmers. I have Sorrell boots rated for -75 a much better choice IMO.